Once, when people talked about welfare reform, it meant trying to improve the lives of people as service users, citizens and claimants. Now it is more likely to mean another attack on people on benefits or a search for an easy way of making public spending cuts. But we can expect to hear much more about welfare reform in the coming months, with a general election pending and politicians on the lookout for easy targets for party-political points scoring and economies.

It was Peter Lilley, as Tory social security secretary, who said he'd "got a little list" of people to stereotype as scroungers. This hate list is longer under New Labour. The groups who regularly feature are some of the poorest and most powerless in our society: lone parents, mental health service users, refugees and asylum seekers, "the unemployed", and young and homeless people. They have few friends in parliament, and few votes are to be lost attacking them.

The irony is that this punitive approach to welfare reform generally has the opposite effect to that promised, creating additional bureaucratic costs and waste, and setting one group against another. The latter may be an unstated intention but it does little for social cohesion. It causes many, who by common consent need help, to keep as far away from state agencies as possible, and they are left struggling on their own.

It is time we agree some rules for talking about welfare reform.

The argument for shifting from universal to targeted means-tested benefits and services has long been that it focuses resources more efficiently and meets the needs of those who really need help, rather than wasting them on people who should be able to manage on their own. But the evidence is that the administration of such provision is always costly and wasteful, sometimes amounting to more than the savings.

When provision isn't universal, there are few with enough power to fight for it, and gradually it is undermined and whittled away. Since only those seen as having "high-level needs" end up qualifying, early intervention and prevention are undermined, problems worsen and costs become bigger in the end.

It is also time for a serious reassessment of what actual benefit – let alone merit – there is in attacking welfare claimants to reduce misuse and "scrounging". Even under the Victorian poor law the lesson was learned that the small hard core of people who may abuse a system tend not to be fazed, shamed or otherwise affected by such punitive policy, but simply find ways round it. What it actually does is put off those people with legitimate entitlement to support, and unnecessarily and inappropriately harass those it should be helping.

It is not as if there haven't been many genuine innovations in social policy to build on. These range from rape crisis centres and women's refuges to phone helplines staffed by the groups they support, sustainable employment schemes, and "user controlled" services developed by service users and their organisations. These remain chronically insecure, underfunded and underdeveloped. Time must be called on the constant reruns of divisive and self-serving attacks on welfare and the devalued groups it serves. Instead, politicians need to adopt the same "evidence-based" approach to welfare they so often talk about outside of the hustings.